2,403 research outputs found

    Laboratory Rearing of \u3ci\u3eLycaeides Melissa Samuelis\u3c/i\u3e (Lepidoptera: Lycaenidae), An Endangered Butterfly in Michigan

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    The Karner blue butterfly (Lycaeides melissa samuelis) is listed as a federally endangered species in the United States. It occurs in oak savanna and pine barren habitats from eastern Minnesota to New Hampshire. In 1994, we successfully reared Karner blue larvae under controlled laboratory conditions for experimental purposes, and report on those rearing methods here. We collected 20 female Karner blue adults of the spring generation from two areas in Michigan, and housed them in cages in an environmental chamber at 240 -26°C for 5 days. The female butterflies produced 154 eggs, of which 72 hatched in an average of 4.5 days, and 68 first instars survived. Eggs, larvae and pupae were kept in a growth chamber at 24°C. Developmental time from egg to adult averaged 26 days; the average duration of each instar ranged from 3 to 4 days, and the average pupal duration was 8 days. Thirty three lab- oratory-reared Karner blue larvae successfully completed the 4 instars, and were released as adults into maternal collection sites. Laboratory rearing may be a viable means of providing Karner blue individuals for reintroduction into areas where the species is extirpated, for supplementation of small populations, or for research. Ultimately, such methods may become an integral part in the recovery of this and other rare invertebrate species

    Nernst branes with Lifshitz asymptotics in N=2 gauged supergravity

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    We discuss two classes of non-supersymmetric interpolating solutions in N = 2, D = 4 gauged supergravity, that flow from either a z = 2 Lifshitz geometry or a conformal AdS background to the near-horizon geometry of a Nernst brane. We obtain these solutions by constructing a z = 2 supersymmetric Lifshitz solution in the STU model from a first-order rewriting of the action, then lifting it up to a five-dimensional background and subsequently modifying this five-dimensional solution by a two-parameter family of deformations. Under reduction, these give four-dimensional non-supersymmetric Nernst brane solutions. This is a step towards resolving the Lifshitz tidal force singularity in the context of N = 2 gauged supergravity and suggests an approach to encoding the Nernst brane in terms of the Schrodinger symmetry group of the holographically dual field theory

    In Their Own Voices: Assessing Student Learning Through Analysis of Reflective Writing

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    In order to assess students\u27 experiences of their service-learning Capstone, researchers used a qualitative design to study 50 students\u27 reflections from seven distinctly different Senior Capstone courses. In these reflections, students demonstrated integrative learning while deepening their understanding of communication, critical thinking, diversity, and social responsibility

    Susceptibility of the Endangered Karner Blue Butterfly (Lepidoptera: Lycaenidae) to \u3ci\u3eBacillus Thuringiensis\u3c/i\u3e Var. \u3ci\u3eKurstaki\u3c/i\u3e Used for Gypsy Moth Suppression in Michigan

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    We investigated the phenological and physiological susceptibility of the endangered Karner blue butterfly (Lycaeides melissa samuelis) to Bacillus thuringiensis var. kurstaki (Bt), a product widely used for gypsy moth (Lymantria dispar) suppression in Michigan and other infested states. We monitored phenology of the bivoltine Karner blue in two regions of Michigan from 1993 to 1995 to determine if larval stages overlapped temporally with the period of Bt application for gypsy moth suppression. Karner blue larvae of the spring generation were found during the period that Bt was applied in nearby areas in 1993 only. However, spring-generation adults or newly laid eggs were observed up to 11 days before applications in 1994 and 1995. Since Karner blue eggs develop within one week, summer-generation larvae were most likely present during or shortly after 1994 and 1995 Bt application periods. These larvae would have been at risk, assuming Bt persistence of 4 to 6 days. Physiological susceptibility of Karner blue larvae to Bt was determined in a laboratory bioassay. Larvae were reared on wild lupine (Lupinus perennis) foliage that was untreated, or sprayed with Bt formulations at rates of 30-37 or 90 BIU/ha. A similar bioassay with second instar gypsy moth larvae on similarly treated white oak (Quercus alba) foliage was conducted concurrently. Karner blue survival was 100%, 27% and 14% on control, low and high Bt treatments, respectively. Early and late Karner blue instars were equally susceptible to Bt. Survival of gypsy moth was 80%, 33% and 5% on control, low and high Bt treatments, respectively, and did not differ significantly from Karner blue survival. We conclude that Karner blue is both phenologically and physiologically susceptible to Bt used for gypsy moth suppression, although the larval generation at risk and extent of phenological overlap may vary from year to year

    Electron Waiting Times in Mesoscopic Conductors

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    Electron transport in mesoscopic conductors has traditionally involved investigations of the mean current and the fluctuations of the current. A complementary view on charge transport is provided by the distribution of waiting times between charge carriers, but a proper theoretical framework for coherent electronic systems has so far been lacking. Here we develop a quantum theory of electron waiting times in mesoscopic conductors expressed by a compact determinant formula. We illustrate our methodology by calculating the waiting time distribution for a quantum point contact and find a cross-over from Wigner-Dyson statistics at full transmission to Poisson statistics close to pinch-off. Even when the low-frequency transport is noiseless, the electrons are not equally spaced in time due to their inherent wave nature. We discuss the implications for renewal theory in mesoscopic systems and point out several analogies with energy level statistics and random matrix theory.Comment: 4+ pages, 3 figure

    Markovian master equations for quantum thermal machines: local vs global approach

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    The study of quantum thermal machines, and more generally of open quantum systems, often relies on master equations. Two approaches are mainly followed. On the one hand, there is the widely used, but often criticized, local approach, where machine sub-systems locally couple to thermal baths. On the other hand, in the more established global approach, thermal baths couple to global degrees of freedom of the machine. There has been debate as to which of these two conceptually different approaches should be used in situations out of thermal equilibrium. Here we compare the local and global approaches against an exact solution for a particular class of thermal machines. We consider thermodynamically relevant observables, such as heat currents, as well as the quantum state of the machine. Our results show that the use of a local master equation is generally well justified. In particular, for weak inter-system coupling, the local approach agrees with the exact solution, whereas the global approach fails for non-equilibrium situations. For intermediate coupling, the local and the global approach both agree with the exact solution and for strong coupling, the global approach is preferable. These results are backed by detailed derivations of the regimes of validity for the respective approaches.Comment: Published version. See also the related work by J. Onam Gonzalez et al. arXiv:1707.0922

    \u3ci\u3eAnoplophora Glabripennis\u3c/i\u3e Within-Tree Distribution, Seasonal Development, and Host Suitability in China and Chicago

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    Established populations of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), were first reported in the United States in New York in 1996, Illinois in 1998, and New Jersey in 2002. A federal quarantine and an eradication program were implemented in 1997, involving tree surveys and removal of infested trees. We recorded the number of A. glabripennis life stages found at several locations along the main trunk and major branches of naturally infested trees in China (species of Populus, Salix, and Ulmus) and Chicago, Illinois (species of Acer, Fraxinus, and Ulmus) during 1999 to 2002. Typically, A. glabripennis initiated attack near the crown base along both the trunk and main branches. The one exception to this pattern was on Populus trees in China that had branches along the entire trunk, in which case A. glabripennis initiated attack along the lower trunk. Larvae were the dominant overwintering stage in both countries. A host suitability index for A. glabripennis was calculated for each tree with the formula: (number of living life stages + number of exit holes) / number of oviposition pits. The mean host suitability index was higher on Populus and Salix than Ulmus in China, and generally higher on Acer and Ulmus than Fraxinus in Chicago. Eleven genera of trees (N = 1465 trees) were infested by A. glabripennis in Chicago; in decreasing order of tree frequency they included Acer, Ulmus, Fraxinus, Aesculus, Betula, Salix, Celtis, Malus, Pyrus, Sorbus, and Tilia. When the proportion of each genus of infested street trees (N = 958 trees in 7 genera) was compared to its proportion of all Chicago street trees based on a 2003 inventory (N = 539,613 trees in 45 genera), A. glabripennis showed a significant preference to infest the genera Acer and Ulmus. Based on our results, inspectors should focus their efforts on upper trunks and lower branches of Acer and Ulmus trees

    Bering - The first deep space mission to map asteroidal diversity, origin and transportation

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    Asteroids are remnants of the material from which the Solar System formed. Fragments of asteroids, in the form of meteorites, include samples of the first solid matter to form in our Solar System 4.5 mia years ago. Spectroscopic studies of asteroids show that they, like the meteorites, range from very primitive objects to highly evolved small Earth-like planets that differentiated into core mantle and crust. The asteroid belt displays systematic variations in abundance of asteroid types from the more evolved types in the inner belt to the more primitive objects in the outer reaches of the belt thus bridging the gap between the inner evolved apart of the Solar System and the outer primitive part of the Solar System. High-speed collisions between asteroids are gradually resulting in their break-up. The size distribution of kilometer-sized asteroids implies that the presently un-detected population of sub-kilometer asteroids far outnumber the known larger objects. Sub-kilometer asteroids are expected to provide unique insight into the evolution of the asteroid belt and to the meteorite-asteroid connection. We propose a space mission to detect and characterize sub-kilometer asteroids between Jupiter and Venus. The mission is named Bering after the famous navigator and explorer Vitus Bering. A key feature of the mission is an advanced payload package, providing full on board autonomy of both object detection and tracking, which is required in order to study fast moving objects in deep space. The autonomy has the added advantage of reducing the cost of running the mission to a minimum, thus enabling science to focus on the main objectives.Comment: 6 pages, 8 figures, Recent Advances in Space Technologies, IEEE proceedings XX, in pres

    Identifying drivers of spatio-temporal dynamics in Barley Yellow Dwarf Virus epidemiology as a critical factor in disease control

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    Barley yellow dwarf virus (BYDV) is one of the most important viral diseases of small grains worldwide. An understanding of its epidemiology is crucial to control this disease in a sustainable way. The virus moves through the agricultural landscape via cereal aphids as vectors. Understanding movement of these aphids in space and time is of key importance and in doing so, the spatial and temporal variables that influence BYDV epidemiology can be identified. The presence of summer hosts, crop rotation, crop diversity, agricultural practices and climate variables are crucial. Through digitalization, spatial (e.g. land-use) and temporal (e.g. weather) information is becoming more readily available. Including this information into a prediction model could improve decision support systems that will rationalize the decision-making process towards a more integrated control of the disease
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